CN101222887B - Prosthesis - Google Patents

Abstract

A prosthesis for a vertebral column has an upper part (10) for attachment to an upper vertebrae, a lower part (12) for attachment to a lower vertebrae and a middle part (11) located between the upper and the lower parts, wherein the upper part has a lower surface portion with a first radius of curvature, the middle part has an upper surface portion with a second radius of curvature and a lower surface with a third radius of curvature and the lower part has an upper surface with a fourth radius of curvature. The centre of the radius of curvature for at least two surfaces is offset rearwardly with respect to a central vertical axis (13) through the upper and lower vertebrae and/or the upper and lower parts. Also defined is device for linking bones, in the form of a band with attachment portions having a number of filaments that provide zones conducive to cellular growth as well as a method of modelling a prosthesis and a process for analysing performance of a prosthesis.

Description

The prosthese that is used for spinal column

Technical field

The present invention relates to mainly as being used in particular for but be not exclusively used in the prosthese of the artificial intervertebral disc of human spinal column.

Background of invention

Human intervertebral disc is safeguarded the connection between the adjacent vertebrae of spinal column.It must fulfil many critical functions such as the carrying that comprises impact power and buffering.And, it must allow the motion of complex form and resist on various arrows, hat and the axial plane single or the combination stress.Through the assistance of muscle ligament (musco-ligamentous) structure around the spinal column, intervertebral disc also must help to safeguard the normal alignment of vertebra in the spinal column.

The all functions of intervertebral disc will be accurately reproduced in ideal artificial intervertebral disc displacement.Yet though described and tested many different artificial intervertebral discs, up to now, they all can not reproduce the ability of intervertebral disc.

The exemplary shortcomings of existing artificial intervertebral disc comprises relaxing of spinal fixation or displacement, material wearing and tearing too early or fault of construction, is difficult to reproduce disappearance normal or that the physiology spinal column segment is moved and brought out normal neutral spinal alignment.

The importance of the proper motion of spinal column and the locomotory mechanism of various motion segments is behaviors of motor segment in bending and the extension movements on the sagittal plane.The basis of this locomotory mechanism is the position of the instantaneous axis of rotation (IAR).IAR changes in spinal column in the bending of any given motor segment (level) and extension movements step by step.

A kind of intervertebral disk prosthesis has been described in the United States Patent (USP) 5674296.Described inner prosthese is made up of the elastomer of substantially elliptical.This inside prosthese sticks between adjacent epipyramis and the following vertebra through L bracket, and said L bracket has separately recessed relatively-protruding lower limb is used to mesh a lip-deep adjacent bone section thickness and this resilient interior prosthese is remained on therebetween.This inside prosthese centrally-located between epipyramis and following vertebra is moved with respect to central pivot of following vertebra to allow epipyramis.

Except that above-mentioned, pad and sealant are set inner prosthese is sealed in the appropriate location between epipyramis and the following vertebra in the front and back location between the vertebra.

United States Patent (USP) 5556431 has been described the inner prosthese of another kind of spinal column, wherein, uses upper plate and lower plate to replace the L bracket of above-mentioned United States Patent (USP).Described inner prosthese comprises the nucleome with last sphere and lower peripheral surface, as shown in the figurely aligns with the central vertical axis of passing upper and lower vertebra.

Opposite with US 5674296, the prosthetic nucleus of this patent has the edge, this edge limitation this nuclear range of movement and even under extreme conditions also guarantee the adhesion of this prosthese.

This patent also discloses the center back displacement of prosthetic joint center with respect to terminal vertebral plate, so that provide in the ventral margin zone of the upper and lower plate of prosthese enough space can receive bone screw.

Other artificial prosthesis comprises that through use the various mechanism of viscoelasticity transmutability nuclear seek to reproduce the normal variation of IAR position.United States Patent(USP) No. 5824094 illustrates this example.Disadvantageous is that the artificial intervertebral disc of these types suffers too early fret wear and stress defective.And the artificial intervertebral disc with metal spring is also failed clinical use.

Above-mentioned all artificial intervertebral discs all have the non-natural stress of final generation and cause artificial intervertebral disc to implant the intrinsic problem of receiver's pain.The present invention provides and aims to provide at least some the selectivity prosthese that can alleviate in the problem related with the prior art prosthese.

Summary of the invention

Should be noted that the beginning of describing in detail at accompanying drawing provides the definition of abbreviation.

According to an embodiment of the present invention, a kind of intervertebral disk prosthesis that can reproduce with the substantially similar locomotory mechanism of human intervertebral disc is provided.

Another embodiment according to the present invention provides a kind of method that is used for analyzing through the motion of adopting unique modeling method to describe the artificial intervertebral disc with active nucleus the prosthese performance.

The another embodiment according to the present invention, analytical method relates to the combination of linear algebra and matrixing.

This analytic process preferably can realize the optimal design of the inner prosthese of intervertebral disc.

Another embodiment according to the present invention provides a kind of intervertebral disk prosthesis with active nucleus, and wherein pivot center can change but can accurately be similar to the normal anatomical center of rotation (ACR) of the existing prosthese with active nucleus.

Another embodiment according to the present invention provides a kind of minimized intervertebral disk prosthesis of unusual tensile side effect in the contiguous ligament structure that makes.

Purpose according to an embodiment of the present invention provides a kind of intervertebral disk prosthesis of resisting the tendency of taking unusual location or orientation when static.

Preferably provide a kind of life expectancy long prosthetic intervertebral disc.

According to an aspect of the present invention; A kind of prosthese that is used for spinal column is provided; It comprises the top that is used to be attached to epipyramis, lower part and the mid portion between top and lower part that is used to be attached to down vertebra; Wherein top comprises that lower surface area, mid portion with first curvature radius comprise surface area part with second curvature radius and the lower surface area with the 3rd radius of curvature; The lower part comprises the surface area with the 4th radius of curvature, and wherein squint with respect to the central vertical axis of passing epipyramis and following vertebra backward in the radius of curvature center at least two surfaces.

Preferably, the relative central vertical axis in the center of the 4th radius of curvature and/or first curvature radius squints backward.

Preferably, squint with respect to central vertical axis backward in the radius of curvature center of all surface.

Each surperficial radius of curvature center preferably is arranged in behind the prosthese 1/3rd.

Mid portion can have subcenter axis and main central axis, and wherein the subcenter axis passes the radius of curvature center on the second and the 3rd surface.

The subcenter axis can tilt with respect to the vertical centre axis.

Preferably, main shaft passes the rear end of mid portion and the center of front end.

The second and the 3rd surface can have similar curvature radius basically.

One of at least one of can have in the second and the 3rd surface in convexity, depression, the cylindrical surface.

Rear end and front end can comprise flat surfaces.

Preferably, the lower surface of lobed upper surface of mid portion and depression.

Preferably, the lower surface depression of the upper surface of mid portion depression and mid portion.

Preferably, the radius of curvature of mid portion upper surface is greater than the radius of curvature of lower surface.

Flat surfaces can be vertical orientated or crooked a little according to the normal one-tenth angular direction (angulation) of vertebra.

It is vertical orientated that flat surfaces preferably is parallel to the vertical axis certain deviation angle that adds deduct.

According to an embodiment, flat surfaces is parallel to time axis.

The radius of curvature center on the 3rd surface is with respect to the radius of curvature center back skew of second surface.

According to an embodiment, the radius of curvature on the 3rd surface has the center that is positioned at perpendicular on the line of main shaft.

According to another embodiment, the radius of curvature on the 3rd surface has the center that is positioned on the line that overlaps with time axis.

According to another embodiment, the radius of curvature of second surface has to be positioned at main shaft and meets at right angles/center on the vertical line.

According to another embodiment, second surface has the radius of curvature that is centered close on the line that overlaps with time axis.

According to another embodiment, the first and the 4th surface have the center respectively with the 3rd with second surface similar curvature radius.

The radius of curvature center on the second and/or the 3rd surface overlaps with the vertical axis that passes the anatomy center of rotation basically.

The length on the second and the 3rd surface can be substantially the same.

Preferably, the end face length of rear end and front end is different.

If the second and the 3rd surface is protruding, then rear end surface can be greater than front end surface.

Preferably, if cave in the second and the 3rd surface, then rear end surface is less than front end surface.

According to an embodiment, the major part of second surface is positioned at before the anatomy center of rotation.

The 3rd surface can have the major part that is positioned at before the anatomy center of rotation.

Each surface preferably has the major part that is positioned at before the anatomy center of rotation and the less important part that is positioned at after it.

Mid portion can be asymmetric.

Preferably, when epipyramis and following vertebra were substantially vertically arranged, the major part of mid portion was positioned at before the anatomy center of rotation.

According to an embodiment, the inferior axis of mid portion near its rest point (upper and lower vertebra balance) if vertical orientated the time not with situation that the vertical axis that passes the anatomy center of rotation overlaps under also as far as possible with its near.

Top can comprise the axis of symmetry of skew to the back-end.

The axis of symmetry can overlap with the radius of curvature center of first surface.

The axis of symmetry preferably passes the anatomy center of rotation.

The lower part can comprise the axis of symmetry that passes the anatomy center of rotation.

Preferably, first and second surfaces have the radius of curvature of coupling basically.

Preferably, third and fourth surface has the radius of curvature of coupling basically.

Top can comprise forefoot area, it with respect to the axis of symmetry greater than rear region.

The lower part can comprise forefoot area, it with respect to the axis of symmetry greater than rear region.

Mid portion preferably can be with respect to top and lower part motion.

The motion of mid portion is preferably limited by the stop device that is positioned at before or after the mid portion.

Stop device can comprise the stub area of top and lower part.

Top and lower part can be fixed in epipyramis and following vertebra and be configured to and form little gap between the respective front ends zone and between the respective rear ends zone, forming big gap.

Preferably, the second and/or the 3rd surface comprises the curved surface zone.

This curved surface zone preferably has the profile of the sphere basically of certain curvature radius.

The second and the 3rd surface preferably has the radius of curvature center of vertical shift.

Preferably, first and second surfaces have radius of curvature similar basically but opposite in sign.

Third and fourth surface has radius of curvature similar basically but opposite in sign.

According to an embodiment, second curvature radius is different with the 3rd radius of curvature.

According to an optional embodiment, the 3rd radius of curvature is greater than or less than first curvature radius.

The 3rd surperficial comparable second surface is more from the central vertical axis skew of vertebra.

According to an embodiment, the prosthese each several part preferably can be designed to asymmetric asymmetric with corresponding to epipyramis that uses them and following vertebra.

Should be appreciated that any all comprises wherein all surface all perk or crooked modification in above-mentioned embodiment and the preferable selection.

Lower part and top preferably comprise the backward motion of stop surfaces with the restriction mid portion in the office, rear portion.

When measuring backward, the length on one of second/the 3rd surface can be greater than another in the past.The 4th surface preferably comprises the smooth forward part of extending from the front end of sweep.

Sweep preferably has the sphere cylinder profile.

It is protruding that end face and bottom surface are preferably.

According to a further aspect in the invention; A kind of device that is used to connect bone is provided; This device comprises band and many fibrils, and band has first and second ends that respectively carry for attaching to the attachment portion of last bone and sending down the fishbone, and many fibrils are configured to provide a plurality of zones that benefit the cell growth.

Said a plurality of zone preferably comprises the space.

Said many fibrils can be configured to form substrate.

According to an embodiment, a plurality of zones comprise a plurality of woven areas.

Fibril can be interleaved in together.

Band preferably comprises thin net (gauze) or grid (mesh).

Band can have intrinsic rigidity.

Preferably, but band is a resilience.

Band is preferably extensible and contractile.

The zone can comprise the space between the fibril.

According to an embodiment, the zone comprises the overlapping region of fibril.

Preferably, the space can be formed by fibril.

According to another embodiment,, fibril forms the intersection grid thereby can being configured to parallel and vertical row.

This device preferably is used to connect upper and lower vertebra.

This band preferably is connected to the front portion of upper and lower vertebra.

Band can be a general planar.

Band can be smooth strip form.

Band can be made up of fabric, metal or polymer.

Dissolved substances is processed when being with preferably by use.

Band preferably can be concertina shape (concertina) or rhombus (lozenge).

According to an embodiment, band provides the axial support of the compression of opposing predeterminated level.

According to another embodiment, band provides the resilience of predeterminated level to stretch.

Each attachment portion can comprise having plate or the band that the permission retaining element is inserted through hole wherein.

According to a further aspect of the invention, a kind of prosthese that is used for vertebra with one or more characteristics of above-mentioned prosthese is provided, wherein when this prosthese was attached to upper and lower vertebra, approximate simulation possible intervertebral disc in top rotated and translational motion.

According to a further aspect of the invention; The method of making the prosthese that is used for vertebra is provided; This method comprises: the model that is provided for designing the prosthese that can simulate intervertebral disc motion mechanism; Use this model manufacturing to comprise the prosthese of top, lower part and mid portion, this prosthese is simulated the locomotory mechanism of intervertebral disc, and wherein simulation possible intervertebral disc in top rotates and translational motion when this prosthese is attached to upper and lower vertebra.

Preferably, the simulation that is provided by prosthese comprises that top is with respect to the anatomy center of rotation perk of intervertebral disc down.

The simulation that is provided by prosthese can be included in moving along intervertebral disc in the radian rotation process that allows.

The simulation that is provided by prosthese can comprise forward and the backward degree that allows to epipyramis of translational motion of intervertebral disc.

It is right to should be noted that for upper and lower vertebra adjacent in the spinal column, and the anatomy center of rotation can change.

According to an embodiment, the radius of curvature on first and second surfaces is selected with respect to following possibly rotating of vertebra based on epipyramis.

According to another embodiment, third and fourth surface has the radius of curvature that is chosen to simulate epipyramis possibility perk amount.

The angle that perk angle that epipyramis allows and expression epipyramis rotate is together very near the angular displacement of epipyramis under the situation that has intervertebral disc between the upper and lower vertebra with respect to following vertebra.

According to a further aspect in the invention, be provided for analyzing the method for the performance of the prosthese that between upper and lower vertebra, uses, this method comprises: the first curvature radius center of confirming prosthese mid portion lower surface; Confirm the second curvature radius of prosthese mid portion upper surface; Between first curvature radius and second curvature radius, provide and be connected; Second curvature radius is rotated the α degree of expression epipyramis perk with respect to first curvature radius; First part that connect is rotated the β degree, thus the length of this part corresponding to from the torsion center of rotation to the epipyramis lower surface or the length at the center of top upper surface, β is corresponding to the angular movement of top on the mid portion upper surface by this; Confirm the anatomy center of rotation; Confirm corresponding to the expectation angle of rotation γ of intervertebral disc with respect to the anatomy center of rotation; Angle γ and angle alpha+beta are compared and design the prosthese of value with the minimized upper and lower radius of curvature of the value center that makes γ-(alpha+beta).

According to another aspect of the invention, the method that is similar to said method is provided, except preceding two definite steps are replaced by the last radius of curvature center of definite prosthese lower part upper surface and the following radius of curvature center of definite prosthese top lower surface.

According to an embodiment, the inferior axis of mid portion is passed in said connection.

According to another embodiment, angle α is corresponding to the angle between the central vertical axis (prosthese axis) of last radius of curvature and upper and lower vertebra.

According to an embodiment, angle β is corresponding to moving the angle that angle forms through connecting first, and this connection overlaps with the central point of the lower surface of epipyramis when moving maximum magnitude with respect to the anatomy center of rotation thus.

The different embodiments according to the present invention, the second and the 3rd surface can be in the following combination any:

Convexity/convexity;

Depression/depression;

Depressions/protrusions;

Convex/concave;

Convexity/cylinder;

Depression/cylinder.

This method preferably comprises confirms first length that connects and the length that second between the central point is connected on radius of curvature center and the epipyramis lower surface down.

The another embodiment according to the present invention; This method relates to the frame that is arranged in the anatomy center of rotation is transformed to the world coordinates system and moves this frame this frame is repositioned at the center of epipyramis lower surface or the point of epipyramis lower surface through translation and rotation transformation, wherein when on the epipyramis infra vertebra when static this point be positioned on the vertical axis that passes the anatomy center of rotation.

Related conversion preferably comprises the algebraical sum matrixing of describing in the preferred embodiments.

According to an embodiment, this method relates to a kind of prosthese of design makes the ligament maximum variation because of the prosthese dislocation be able to minimize.The prosthese dislocation can be by the horizontal range value defined between prosthese axis and the patient's center of rotation (the value L among the value Ldsk among Fig. 5 a, the 5c and Figure 19 A and the 19B).

According to another embodiment, this method relates to a kind of mechanism of design makes ligament stretch with following mode: crooked with stretch in receive more hightension and receive minimum tension at neutral position (neutral position).This mechanism will provide the restoring force of tending to prosthese is moved back to neutral position.

According to another aspect of the invention, a kind of prosthese modeling method is provided, comprising:

The frame matrix F R1 of the 2D at least that the coordinates of reference points that definite in situ expression is positioned at the ACR place of linear vertebra to the prosthese between the upper and lower vertebra is;

Confirm the reference frame B1 of the point at the CUPR place that the frame FR1 with respect to the ACR place representes;

Wherein $\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="S2006800197085E00011.png,S2006800197085E00151.png"\; state="\{\{state\}\}">B</figure-callout>}1=\left[\begin{array}{ccc}1& 0& \mathrm{<figure-callout\; id="0"\; label="l"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">l</figure-callout>}\\ 0& 1& \mathrm{<figure-callout\; id="0"\; label="p"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">p</figure-callout>}\\ 0& 0& 1\end{array}\right]$

Wherein 1=is from the distance of ACR along the x axle to CUPR; Or

P=is from the distance of ACR along the y axle to CUPR.

B1 is rotated α to generate new frame B2=B1 * T, and middle α is the angle of rotation of CLPR about CUPR; And T is a transformation matrix:

$\left[\begin{array}{ccc}\cos \mathrm{\&alpha;}& -\sin \mathrm{\&alpha;}& \mathrm{\&Delta;x}\\ \sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}& \mathrm{\&Delta;<figure-callout\; id="0"\; label="y"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">y</figure-callout>}\\ 0& 0& 1\end{array}\right]$

With frame B2 along the distance b of y axle translation from CUPR to CLPR to generate frame B3, wherein:

Use T that frame B3 is rotated the β degree generating new frame,

B4＝B3×T

Wherein β is the angle of rotation of the some B of epipyramis with respect to CLPR.

With frame B4 along the translation of y axle the distance C from CLPR to a B to generate new frame B5

Wherein $\mathrm{<figure-callout\; id="5"\; label="B"\; filenames="S2006800197085E00281.png"\; state="\{\{state\}\}">B</figure-callout>}5=\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& \mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">C</figure-callout>}\\ 0& 0& 1\end{array}\right]$

With frame B5 along the translation of x axle from a B to an E apart from l, with the vertical axis coaxial line that passes ACR, to generate new frame B6

Wherein translation matrix does

$\left[\begin{array}{ccc}1& 0& \mathrm{<figure-callout\; id="0"\; label="l"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">l</figure-callout>}\\ 0& 1& 0\\ 0& 0& 1\end{array}\right]$

Use T that frame A1 is rotated γ to generate new frame A2.

γ=epipyramis is with respect to the normal rotation of ACR.

Distance h from ACR to an E is to generate A3 along the translation of y axle with A2, and wherein translation matrix does

$\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& \mathrm{<figure-callout\; id="0"\; label="h"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">h</figure-callout>}\\ 0& 0& 1\end{array}\right]$

Relatively B6 and A3 with definite prosthese to simulating of the locomotory mechanism of intervertebral disc have how definite.

According to an embodiment, frame B6 and A2 rotate γ around overall reference frame A1 ⁰To generate new frame A4 and B7.

Preferably, comparison step comprises that to following equation at least one find the solution minima.

A3(1，3)-B6(1，3)＝0 A4(1，3)-B7(1，3)＝0

A3 (2,3)-B6 (2,3)=0 or A4 (2,3)-B7 (2,3)=0

But the numeral in its bracket is represented the row and column of application matrix respectively.

According to another embodiment, comparison step comprises the simultaneous equations of the equivalent row and column of finding the solution A4 and B7.

Reference frame A1 is preferably overall reference frame.

Should be appreciated that the use of word " simulation " is intended to by wide in range explanation to contain similar but not definite reproduction.

Word " prosthese " is intended to contain any artificial insert of the assembly with arbitrary number.

The modeling method that is used to analyze the prosthese performance has preferably been described has active nucleus and by the motion of the artificial intervertebral disc of contiguous ligament tissue constraint.

Modeling method preferably can be used for the various design parameters of active nucleus prosthese so that reproduce more accurately normal disc IAR the position and minimize following in the flexion/extension motor process or being in to follow under abnormal motion path and/or the static situation or be on the sagittal plane unusual neutral tendency of arranging.

Through using modeling method to illustrate: for the prosthese that has active nucleus with upper plate and lower plate, wherein upper plate and lower plate have the joint be connected surperficial, one preferred embodiments according to the present invention, suitable following content:

1. radius is big more, needs the translation must be many more for given change in orientation nuclear.

2. radius is more little, needs translation to lack more for given change in orientation nuclear.

3. for the given variation of position and orientation:

(a) pivot center of prosthese is near more apart from the normal anatomical center of rotation, and the length that LLS need change is more little.

(c) if the prosthese pivot center shifts forward to the anatomy center of rotation, then biconvex rise or the upper and lower articular surface difference of the prosthese of dual recess big more, LLS need stretch manyly more.

(d) if the pivot center of intervertebral disk prosthesis shifts forward to the normal anatomical center of rotation, then in BENDING PROCESS, the final position of epipyramis will be confirmed by PLL and the tensile ability of LLS with orientation.

Thereby, there are following four possibilities:

(i) PLL can not La Shen &LLS can not stretch-epipyramis can not move,

(ii) PLL can La Shen &LLS can not stretch-epipyramis will be in bow-backed position,

(iii) PLL can La Shen &LLS can stretch-epipyramis is with instability and be in non-anatomical location/orientation,

(iv) PLL can not can stretch-in clinical practice, unlikely take place by La Shen &LLS.

Thereby for the epipyramis that in BENDING PROCESS, is in given orientation, essential stretching of LLS and therefore final vertebra position will be no longer normal.

(e) if the pivot center of intervertebral disk prosthesis shifts forward to the normal anatomical center of rotation, then in stretching process, the final position of epipyramis is confirmed by the stretch capability of LLS with orientation fully.This is because ALL excises in the orthopaedic surgical operations method.Thereby, there are following two kinds of possibilities:

I) LLS can not stretch-epipyramis will be in the position that lordosis must be littler than normal condition.

Ii) LLS can stretch-epipyramis is in normal orientation, but has the out-of-the way position that the stretching by LLS allows.

4. the prosthese pivot center is incited somebody to action near the motion of normal ACR:

I) stretching and the needs of shortening of ligament in normal crooked and extension movements are minimized.

Ii) optimize vertebra is in normal orientation and position in crooked and extension movements ability.

5. the prosthese axis has been introduced two new problems towards the motion of the normal anatomical position of the ACR that is positioned at latter half below, dish gap:

I) have nuclear that existing biconvex plays design in BENDING PROCESS backward translation cause neutral compression.A kind of solution is to use dual recess nuclear.Dual recess nuclear mechanism can make nuclear in BENDING PROCESS, move forward and in stretching process, move backward.

Ii) in some embodiments, nuclear becomes about the prosthese axis asymmetric.Therefore, the rotation around this axis produces neutral compression.A kind ofly prevent that the solution of rotating around the prosthese axis from being cylindrical but not spherical through one of two prosthetic joints are processed.Another kind of solution is that two prosthetic joints are processed spheroid-like.A kind of solution is arranged is that to make two surfaces be sphere but mechanical arresting device is set or guide vane (guide fin).

6. in another embodiment, use mathematical procedure to optimize the disc mechanism that is made up of crooked upper joint and hypozygal, wherein the arc center is below the dish substrate and radius equates to locate.This can allow the variation of prosthese pivot center upright position, but it is limited in dish substrate below.Some desired locations not that this prosthese can not be realized it will be apparent to those skilled in the art.

Thereby, at excision anatomy ALL so that front end insert in after free disc prosthesis, this prosthese does not exist under the suitable tensile situation in being close to ligament structure can not correctly bring into play function.Constraint is set in disc prosthesis will tighten prosthese/vertebra interface and prosthese is fluffed.Yet, in some cases, possibly expect to allow to be provided with the material of the non-joint upper surface of the non-joint lower surface that is attached to top and lower part.This material can be made up of the inflexible any suitable elastomeric material that can required mode increases structure (for example, but be not limited to polymer).Though can use mathematical procedure design to make the minimized prosthese of unusual tensile effect in the contiguous ligament structure, this prosthese supports through artificial ALL is set preferably that also this ALL is attached to the vertebral body front portion and separates with intervertebral disk prosthesis.

Preferably, at excision anatomy LLL so that front end insert in after free disc prosthesis, this prosthese does not exist under the suitable tensile situation in being close to ligament structure can not correctly bring into play function.Constraint is set in intervertebral disk prosthesis will tighten prosthese/vertebra interface and prosthese is fluffed.Though can use mathematical procedure design to make the minimized prosthese of unusual tensile effect in the contiguous ligament structure, this prosthese supports through artificial ALL is set preferably that also this ALL is attached to the vertebral body front portion and separates with intervertebral disk prosthesis.

In the summary of the invention of appended claims and preceding text; Except context needs perhaps because Explicit Language or the necessary hint; In each embodiment of the present invention; Word " comprises " or is used to comprising property notion such as the variant of " comprising " or " containing ", promptly points out the appearance of said characteristic but do not get rid of the appearance of further feature or attached.

The accompanying drawing summary

Preferred embodiments of the present invention is described through by way of example referring now to accompanying drawing, in the accompanying drawing:

Fig. 1 illustrates the sketch map of the prior art prosthese between epipyramis and the following vertebra;

Fig. 2 illustrates the dual link model of prosthese according to an embodiment of the present invention;

Fig. 3 illustrates the motion sketch map of normal disc around the anatomy center of rotation;

Fig. 4 illustrates the sketch map of the upper and lower vertebra that has overall reference frame of preferred embodiments according to the present invention;

Fig. 5 A and 5C illustrate prosthese (be respectively protrusion/depression and dual recess nuclear) and the sketch map of upper and lower vertebra of translation features of the model of embodiment preferred embodiments according to the present invention;

Fig. 5 B and 5D illustrate the rotation feature of Fig. 5 A and 5C institute representation model;

The sketch map of epipyramis and biconvex nuclei of origin prosthese when Fig. 6 illustrates hunchback;

The sketch map of epipyramis and convex/concave nuclear when Fig. 7 illustrates hunchback;

Fig. 8 illustrates the sketch map that epipyramis and biconvex under maximum ligament tension (MLS) constraint play prosthese;

Fig. 9 illustrates the sketch map of the prosthese of the nuclear with upper surface convexity and lower surface depression, and wherein epipyramis is under maximum ligament tension (MLS) constraint;

When Figure 10 A illustrates upper and lower vertebra and is in resting position according to the prosthese of another embodiment;

Prosthese shown in Figure 10 A when Figure 10 B illustrates epipyramis and rotates 10 °;

Figure 11 illustrate epipyramis and following vertebra when static according to the present invention the prosthese of another embodiment;

Prosthese shown in Figure 11 when Figure 12 illustrates epipyramis and rotates 10 °;

Figure 13 A illustrates the vertical view of the prosthese of another embodiment according to the present invention;

Figure 13 B illustrates along the cross-sectional view of the prosthese of Figure 13 A of transversal A-A intercepting;

Figure 13 C illustrates along the cross-sectional view of prosthese shown in Figure 13 A of transversal B-B intercepting;

Figure 13 D illustrates the vertical view of prosthese shown in Figure 13 A;

Figure 13 E illustrates the rearview of prosthese shown in Figure 13 A;

Figure 13 F illustrates the side view of prosthese shown in Figure 13 A, and wherein the rear end is represented in the left-hand side;

Figure 14 illustrates the angled view of the prosthese of another embodiment according to the present invention;

Figure 15 A illustrate upper and lower vertebra when static according to the present invention the diagrammatic side view of the prosthese of another embodiment;

The prosthese of Figure 15 A when Figure 15 B illustrates epipyramis and rotates 10 °;

Figure 16 illustrates the diagrammatic side view of the prosthese of another embodiment according to the present invention;

Figure 17 illustrates the diagrammatic side view of the prosthese of another embodiment according to the present invention; And

Figure 18 illustrates the front view according to the ligament of the present invention of an embodiment;

Figure 19 A illustrates the transversal end view drawing of the prosthese on the equilbrium position of another embodiment according to the present invention;

Figure 19 B illustrates the prosthese of unstable locational Figure 19 A;

Figure 20 A and 20B illustrate the three-dimensional curve analysis of diverse location of the prosthese of the nuclear with upper surface convexity and lower surface depression according to an embodiment of the present invention;

The 2D curve representation of the prosthese that Figure 21 illustrates among Figure 20 to be analyzed;

The biconvex that illustrates Figure 22 plays the 3D tracing analysis of prosthese;

Figure 23 illustrates ligament length plays the angular movement of prosthese with respect to biconvex 2D curve; And

Figure 24 illustrates the 3D tracing analysis of dual recess prosthese according to an embodiment of the present invention.

The specific embodiment

In order to help to understand the present invention, below set forth used term.

Term:

A. center of rotation (COR): object rotates around it to arrive the point of desired location and orientation under zero translation situation.(translation is defined in the pure linear movement of any direction under the situation that does not change orientation)

B. instantaneous axis of rotation (IAR): the COR any instantaneous COR position when accurate location changes in (such as crooked and stretch) process of between two-end-point, moving.

C. anatomy center of rotation (ACR): the center of rotation of non-ill neck movement section between the two-end-point.

D. go up prosthese radius and following prosthese radius (UPR&LPR): the upper and lower radius of curvature of intervertebral disk prosthesis.

E. go up prosthese center of radius and following prosthese center of radius (CUPR&CLPR): the central point of upper and lower intervertebral disk prosthesis radius.Play intervertebral disk prosthesis nuclear for biconvex, CUPR is positioned at the below and CLPR is positioned at the top.

F. prosthese axis (PA): the line that connects CUPR and LUPR.

G. collateral ligament structure (LLS): initial and be attached to the ligament at the lower side edge of epipyramis from the upper side edge of vertebra down, it along from ACR upwards with forward the line of departure and minimum in spinal column segment extension around the bending of ACR and extension movements.

H. simplified side ligament structure (SLLS): describe between single line or the vertebra of mathematics behavior of LLS and connect.

I. anterior longitudinal ligament (ALL): front side ligament structure.

J. posterior longitudinal ligament (PLL): rear side ligament structure.

K. mathematical procedure: relate to the linear algebra of the motion that can be used for describing artificial intervertebral disc and the mathematical procedure of matrixing with active nucleus.

Fig. 1 illustrates the prosthese with biconvex nuclei of origin of the prior art prosthese of expression shown in the example in the U.S. Pat 5674296 of authorizing Bryan.

Becoming from Fig. 1, it is obvious that, and epipyramis 10 can rotate and examine 11 with respect to nuclear 11 and can rotate with respect to vertebra 12 down.

Before appeared because in fact have two angles of rotation, so this prosthese can take any required location to simulate normal rotation.Yet the analysis of preferred embodiments illustrates according to the present invention, and the definite simulation of normal rotation is impossible, but might design the prosthese with approximate proper motion.

Increment normal rotation on the sagittal plane is carried out around instantaneous axis of rotation.When on than wide-angle, measuring, this ICR is mobile slightly, though in lumbar vertebra and cervical vertebra, all take place, usually in the latter half of infra vertebra.

According to an embodiment of the present invention, the motion of epipyramis 10 can be through describing it as the dual link analysis with connection 14 and 15 as shown in Figure 2.Point CUPR keeps fixing in world coordinates.This motion is visual to connect 14 and 15 serial movement.Begin most, epipyramis 10, nuclear 11 and some CLPR rotate the α degree around a CUPR.Descend vertebra 12 to rotate the β degree then around the position (CLPR1) that CLPR newly turns to.

The inferior axis (not shown) of nuclear 11 keeps vertical with the A that is connected that self passes 11 axis of nuclear.Therefore, nuclear 11 moves on the direction identical with epipyramis 10.In bending, nuclear 11 travels forward, and in stretching, extension, nuclear 11 will move backward.

When the above-mentioned prosthese of design, the spinal motion when having the intervertebral disc operate as normal between the upper and lower vertebra is simulated in expectation as far as possible approx.Therefore for the reference frame of this proper motion is provided,, the figure shows near the fixedly motion of the normal disk (intervertebral disc) of center of rotation (ACR) with reference to Fig. 3.The respective point motion of have a few on the vertebra 10 on vertebra 18, and to describe from epipyramis 10 positions to the conversion of the motion of the arbitrfary point of vertebra 16 down be around ACR angle of rotation γ.Line 17 and 18 illustrates positional information and angle information.These characteristics are defined as position and orientation.

Thereby; For any artificial intervertebral disc mechanism of reproducing motor behavior shown in Figure 3, essential from line segment 17 move to line segment 18 and when motion finishes the position of the line segment C1-D1 of artificial intervertebral disc mechanism (prosthese) must mate with the line segment 18 Fig. 3 with orientation.

Refer again to Fig. 2, thereby the position of vertebra and orientation are by angle α and β and the complete description of length that is connected 14 and 15.Thereby, if the mechanism among Fig. 2 can imitate the mechanism among Fig. 3, then must there be the position that makes two vertebras variable α all identical, β, 14,15 combination with orientation.

The position of object can described easily with orientation through using linear algebra in the two-dimensional space.For the position and the orientation of two-dimensional structure in the complete description two-dimensional space, can add coordinate system to this system.This coordinate system is called as frame.Have a few in the moving object has fixed coordinates in new frame, and this frame is regarded as motion in another coordinate system (being generally the overall situation or " integral body " coordinate system).Fig. 4 illustrates the frame FR1 that is additional to motion vertebra among Fig. 3.The initial point of this frame is from overall frame G origin displacement position vector p.The orientation of frame FR1 is provided by x axis unit vector n and the y axis unit vector o of FR1.

In matrix notation, frame FR1 can be described as:

$\mathrm{<figure-callout\; id="1"\; label="FR"\; filenames="S2006800197085E00011.png,S2006800197085E00151.png"\; state="\{\{state\}\}">FR</figure-callout>}1=\left[\begin{array}{ccc}{\stackrel{\&RightArrow;}{n}}_x& {\stackrel{\&RightArrow;}{o}}_x& {\stackrel{\&RightArrow;}{p}}_x\\ {\stackrel{\&RightArrow;}{n}}_y& {\stackrel{\&RightArrow;}{o}}_y& {\stackrel{\&RightArrow;}{p}}_{\mathrm{<figure-callout\; id="0"\; label="y"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">y</figure-callout>}}\\ 0& 0& 1\end{array}\right]$

Wherein

Be additional to the coordinate x on the frame FR1, y a bit can be transformed in the world coordinates through coordinate vector with this point among the matrix F R1 premultiplication FR1:

Can be such as any frame of FR1 through multiplying each other conversion with transformation matrix T with following characteristic:

$T=\left[\begin{array}{ccc}\cos \mathrm{\&alpha;}& -\sin \mathrm{\&alpha;}& \mathrm{\&Delta;x}\\ \sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}& \mathrm{\&Delta;<figure-callout\; id="0"\; label="y"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">y</figure-callout>}\\ 0& 0& 1\end{array}\right]$

α=angle of rotation wherein

The variation of Δ x and Δ y=x and y position.

If matrix M is by frame FR1 premultiplication, then frame FR1 will rotate and translation on overall reference frame axis direction around fixed overall reference frame initial point.If matrix M is taken advantage of by the FR1 right side, then FR1 will rotate and translation on the axis direction of this motion frame (FR1) around the initial point of motion frame (FR1).

Fig. 5 A to 5D illustrates the supposition prosthese with protruding upper surface and recessed lower surface.From analysis purpose, there are the mechanical connection that constitutes by the line segment AD that rotates around an A and another connection that constitutes by line segment DB.The DB rigidity is attached to epipyramis and last prosthese end plate.Reference frame has been affixed to an ACR.Another reference frame has been affixed to an A.

Consider the variable among Fig. 5 A and the 5C, BFR1 should have following value that it is obvious that-in overall reference frame AFR1, represent:

$\mathrm{<figure-callout\; id="1"\; label="BFR"\; filenames="S2006800197085E00011.png,S2006800197085E00151.png"\; state="\{\{state\}\}">BFR</figure-callout>}1=\left[\begin{array}{ccc}1& 0& \mathrm{<figure-callout\; id="0"\; label="Ldsk"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">Ldsk</figure-callout>}\\ 0& 1& \mathrm{<figure-callout\; id="0"\; label="Pdsk"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">Pdsk</figure-callout>}\\ 0& 0& 1\end{array}\right]$

Be additional to the top vertebra for reference frame BFR1 is transformed at a B, must carry out shown in Fig. 5 B and the 5D with down conversion.

1. rotate the α degree to produce new frame BFR1R

$\mathrm{BFR}1R=\mathrm{<figure-callout\; id="1"\; label="BFR"\; filenames="S2006800197085E00011.png,S2006800197085E00151.png"\; state="\{\{state\}\}">BFR</figure-callout>}1*\left[\begin{array}{ccc}\cos \mathrm{\&alpha;}& -\sin \mathrm{\&alpha;}& 0\\ \sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}& 0\\ 0& 0& 1\end{array}\right]$

The normal convention of considering turn is counterclockwise, and α is minus in Fig. 1.

In reference frame BFR1R downwards translation Bdsk to produce new frame BFR2:

$\mathrm{<figure-callout\; id="2"\; label="BFR"\; filenames="S2006800197085E00271.png,S2006800197085E00291.png"\; state="\{\{state\}\}">BFR</figure-callout>}2=\mathrm{BFR}1R*\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& -\mathrm{<figure-callout\; id="0"\; label="Bdsk"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">Bdsk</figure-callout>}\\ 0& 0& 1\end{array}\right]$

3. in the reference frame of self, BFR2 is rotated the β degree to produce new frame BFR2R:

$\mathrm{BFR}2R=\mathrm{<figure-callout\; id="2"\; label="BFR"\; filenames="S2006800197085E00271.png,S2006800197085E00291.png"\; state="\{\{state\}\}">BFR</figure-callout>}2*\left[\begin{array}{ccc}\cos \mathrm{\&beta;}& -\sin \mathrm{\&beta;}& 0\\ \sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}& 0\\ 0& 0& 1\end{array}\right]$

In reference frame BFR2R translation Cdsk to produce new frame BFR3:

$\mathrm{BFR}3=\mathrm{BFR}2R*\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& \mathrm{<figure-callout\; id="0"\; label="Cdsk"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">Cdsk</figure-callout>}\\ 0& 0& 1\end{array}\right]$

BFR3 is affixed to epipyramis and has the orientation of epipyramis at a B now.BFR3 (1,3) (the 1st row the 3rd row) contain the x coordinate of expression point B function f (α, β) and BFR3 (2,3) contain the y coordinate of expression point B function g (α, β).BFR3 (1,1) contain the cosine of an angle that expression forms by top vertebra and overall reference frame function k (α, β).

Consider another linear translation Ldsk among the reference frame BFR3 (epipyramis).This produces new frame BFR4 at an E

$\mathrm{<figure-callout\; id="4"\; label="BFR"\; filenames="S2006800197085E00151.png,S2006800197085E00271.png"\; state="\{\{state\}\}">BFR</figure-callout>}4=\mathrm{BFR}3*\left[\begin{array}{ccc}1& 0& -\mathrm{<figure-callout\; id="0"\; label="Ldsk"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">Ldsk</figure-callout>}\\ 0& 1& 0\\ 0& 0& 1\end{array}\right]$

Equivalent function f, g and k represent (unaltered) angle of orientation of coordinate and the epipyramis of an E now.Through carrying out matrix operations, can illustrate

f(α，β)＝-(cosα·cosβ-sinα·sinβ)·Ldsk+(-cosα·sinβ-sinα·cosβ)·Cdsk+sinα·Bdsk+Ldsk)

........................(1)

The x coordinate of f=point E wherein

g(α，β)＝-(sinα·cosβ+cosα·sinβ)·Ldsk+(cosα·cosβ-sinα·sinβ)·Cdsk-cosα·Bdsk+Pdsk)

.....................(2)

The y coordinate of g=point E wherein

And

k(α，β)＝cosα·cosβ-sinα·sinβ?...............(3)

The cosine of angle between k=epipyramis and the overall reference frame wherein.

Can know that from Fig. 5 because AFR1 is overall reference frame, its value is:

$\mathrm{<figure-callout\; id="1"\; label="AFR"\; filenames="S2006800197085E00011.png,S2006800197085E00151.png"\; state="\{\{state\}\}">AFR</figure-callout>}1=\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& 0\\ 0& 0& 1\end{array}\right]$

Frame AFR2 can be through deriving frame AFR1 rotational angle γ (the required rotation of normal disc), to produce AFR1R:

$\mathrm{AFR}1R=\mathrm{<figure-callout\; id="1"\; label="AFR"\; filenames="S2006800197085E00011.png,S2006800197085E00151.png"\; state="\{\{state\}\}">AFR</figure-callout>}1*\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& -\sin \mathrm{\&gamma;}& 0\\ \sin \mathrm{\&gamma;}& \cos \mathrm{\&gamma;}& 0\\ 0& 0& 1\end{array}\right]$

Now can be with frame AFR1R along the y axis translation value Adsk of AFR1R to produce frame AFR2

$\mathrm{<figure-callout\; id="2"\; label="AFR"\; filenames="S2006800197085E00271.png,S2006800197085E00291.png"\; state="\{\{state\}\}">AFR</figure-callout>}2=\mathrm{AFR}1R*\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& \mathrm{<figure-callout\; id="0"\; label="Adsk"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">Adsk</figure-callout>}\\ 0& 0& 1\end{array}\right]$

$\mathrm{<figure-callout\; id="2"\; label="AFR"\; filenames="S2006800197085E00271.png,S2006800197085E00291.png"\; state="\{\{state\}\}">AFR</figure-callout>}2=\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& -\sin \mathrm{\&gamma;}& -\sin \mathrm{\&gamma;}\&CenterDot;\mathrm{Adsk}\\ \sin \mathrm{\&gamma;}& \cos \mathrm{\&gamma;}& \cos \mathrm{\&gamma;}\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="Adsk"\; filenames="S2006800197085E00271.png,S2006800197085E00281.png"\; state="\{\{state\}\}">Adsk</figure-callout>}\\ 0& 0& 1\end{array}\right]$

AFR2 (1,3) should comprise the x coordinate of an E and the y coordinate that AFR2 (2,3) should comprise an E now

Make function s (γ)=AFR2 (1,3) (x coordinate) ... ... ... ... .. (4)

Make function t (γ)=AFR2 (2,3) (y coordinate) ... ... ... ... .. (5)

Thereby from equality 1 and 2, frame AFR2 and BFR4 are positioned at same point (E):

s(γ)＝f(α，β) ..............................(6)

t(γ)＝g(α，β)?...............................(7)

Equality 6 and 7 expressions have two simultaneous equations of two variablees.In order to make mechanism can accurately simulate the motion of normal disc, AFR2 and BFR4 must equate thus:

AFR2＝BFR4 ..............................(8)

Can find out, for following formula takes place and equality 6 and 7 establishments, thereby

λ＝α+β.....................................(9)

Can illustrate through digital form, not have the real solution that satisfies equality 6,7 and 8.For the crooked angle γ of given normal disc, separating to prosthese of angle α and β will be located with respect to bow-backed (Kyphosis) or lordosis (Lordosis).Fig. 6 be illustrated in the E constraint identical (constraint 1) with normal prosthese down trial will have the effect of crooked 10 degree of existing prosthese of dual recess.Equality 6,7 and 8 separate and obtain α and equal-10.72 ° and β and equal-18.26 °.Dotted line representes to rotate around ACR 10 ° actual intervertebral disc, and this part representes that the hunchback that keeps an E to have same coordinate separates.This part is the position of 0 ligament tension (ZLS).

Fig. 7 is illustrated in that the E constraint identical with normal prosthese (constraint 1) will have the upper surface convexity down and the effect of crooked 10 degree of prosthese of the nuclear of lower surface depression.Equality 6,7 and 8 separate and obtain α and equal 5.71 ° and β and equal-7.71 °.Dotted line is represented the actual intervertebral disc around 10 ° of ACR rotations.This part representes that the hunchback that keeps an E to have same coordinate separates, but bow-backed state is much littler than biconvex nuclei of origin prosthese.This part is the position of zero ligament tension (ZLS).

In Fig. 7, trial is shown prosthese is stretched 10 ° effect.Equality 6,7 and 8 separate and draw α and equal-1.55 ° and β and equal 4.75 °.The dotted line of epipyramis is also represented the actual intervertebral disc around 10 ° of ACR rotations.This part representes that the lordosis that keeps an E to have same coordinate separates.This part is represented 0 ligament tension position (ZLS).

Other method of constraint is added in existence to this assembly.Other useful constraint be the bottom plate with epipyramis be constrained to ' normally ' situation under the bottom plate of epipyramis parallel and make distance minimization therebetween.This can be through realizing around overall reference frame AFR1 rotation γ degree frame BFR4 and AFR2 to produce new frame AFR3 and BFR5.

$\mathrm{AFR}3=\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& -\sin \mathrm{\&gamma;}& 0\\ \sin \mathrm{\&gamma;}& \cos \mathrm{\&gamma;}& 0\\ 0& 0& 1\end{array}\right]\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="AFR"\; filenames="S2006800197085E00271.png,S2006800197085E00291.png"\; state="\{\{state\}\}">AFR</figure-callout>}2$

$\mathrm{<figure-callout\; id="5"\; label="BFR"\; filenames="S2006800197085E00281.png"\; state="\{\{state\}\}">BFR</figure-callout>}5=\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& -\sin \mathrm{\&gamma;}& 0\\ \sin \mathrm{\&gamma;}& \cos \mathrm{\&gamma;}& 0\\ 0& 0& 1\end{array}\right]\&CenterDot;\mathrm{<figure-callout\; id="4"\; label="BFR"\; filenames="S2006800197085E00151.png,S2006800197085E00271.png"\; state="\{\{state\}\}">BFR</figure-callout>}4$

Because two x coordinates necessary identical (0) are then parallel for two end plates

AFR3(1，1)＝1(cos(0)＝1) .......... (10)

And

BFR5(1，3)＝AFR3(1，3)＝0 ............................(11)

Fig. 8 illustrates the effect of adding the angle of bend coupling of this constraint (constraint 2) and trial and ' normally ' motor segment to the existing prosthese with biconvex nuclei of origin.Can see that under this constraint, two epipyramises can not be overlapping and will be put the ligament that ACR is connected with E and must stretch above its normal length.Under the parallel constraint of end plate, equality 6,7 and 8 knot obtain α and equal-1.61 ° and β and equal-8.39 °.Dotted line is represented to represent to keep making parallel and its spacing the separating from minimum point of end plate around the actual intervertebral disc of 10 ° of ACR rotations and gained position.Therefore, this constraint is called as maximum ligament tension (MLS).The prosthese that Fig. 9 illustrates to the nuclear with upper surface convexity and lower surface depression adds the effect that this constraint (retraining 2) also attempts spending with 10 of ' normally ' motion the bending coupling.Can find out that two epipyramises can not be overlapping and the ligament that ACR is connected to E must be stretched above its normal length.Under the parallel constraint of end plate, equality 6,7 and 8 knot obtain α and equal-12.68 ° and β and equal-2.68 °.Dotted line is represented the actual intervertebral disc around 10 ° of ACR rotations, and parallel and its spacing the separating from minimum point of end plate represented to keep making in the gained position.Therefore, this constraint is called as maximum ligament tension (MLS).

In Fig. 6 and 7, the ligament that ACR is connected to E does not stretch, and the substitute is prosthese and causes bow-backed or lordotic angle in an E place rotation.This constraint is defined as zero ligament tension (ZLS).

In cervical vertebra, there is good anatomical evidence: only exist more weak posterior longitudinal ligament and master ligament from beginning dispersion near the normal anatomical center of rotation (ACR) of this vertebra.Because anterior longitudinal ligament is necessary to damage through surgical method, the cardinal ligament constraint in the cervical vertebra can be approximate by ligament ACR-E.Under the situation that does not have effective posterior longitudinal ligament; The constraint that the cervical vertebra disc prosthesis of having reason to believe type shown in Figure 6 should show as motion is the constraint of ZLS type; And should in bending, be easy to hunchback, and in stretching, extension, be easy to lordosis/back slippage (retrolisthesis).

In the waist awl, it is much tough and tensile that posterior longitudinal ligament is wanted.Therefore, waist awl is preferential attempts using the constraint MLS ligament ACR-E that stretches.Fibrous ring seldom allows like this, and limit flexion is answered in suggestion in theory.

Regardless of particular condition, giving the physical constraint in the price fixing gap will be the combination of constraint ZLS and MLS.The angle of being realized by vertebra in the ZLS situation and poor (the Delta A) of required angle (Г-(alpha+beta)) are that prosthese can not mate measuring of required proper motion.Poor (the Delta L) of ligament ACR-E and Len req also is that this prosthese can not mate measuring of required proper motion.

The mathematical equation of more than deriving is optimized to minimize Delta A or Delta L or both design variable in 2 articular prosthesis.Through minimizing Delta A or Delta L, this prosthese more has an opportunity to optimize the simulation normal condition.

Through using the simulation of above mathematical analysis, following situation is set up.

Make Delta A almost minimize to zero through variables L dsk being reduced to zero.This has makes ACR be positioned at the effect on the prosthese axis axially back the moving of prosthese.On this position, be positioned at dish gap location or all positions below it on the prosthese axis for ACR, it is very little that DeltaA keeps.

DeltaA is minimized when upper and lower prosthetic joint approximately equal.

DeltaA when the joint radius is big, minimized and the situation of DeltaA in small radii under become big.

DeltaA is preferably between 3 ° and 5 °.

The translation of nuclear is big and hour said translation is less when this radius when the prosthese radius is big.

Therefore, disclosed prosthese is sought:

/ 3rd places behind intervertebral disc move with the prosthese axis.

Select the optimum radius in upper and lower joint.

When making these variations, produce two problems.

In some embodiments, the nuclear of prosthese no longer the symmetry and when it rotated, it may be inserted in the spinal canal.

Because the prosthese axis is located backward, so nuclear has the danger of invading spinal cord.

Based on above-mentioned mathematical procedure, prosthese is with by two end plates, intermediate active nuclear with before being respectively applied for the independence that is attached to upper and lower vertebra simply and is constituted.

Figure 13 A to 13E illustrates another embodiment of the present invention, and wherein prosthese is made up of the nuclear 50 with concave upper surface and lower surface 51,52.Upper plate 53 has convex lower surface 54 and lower plate 55 has protruding upper surface 56.

Lower surface 52,56 is cylinder (rotation and translational motion) but not sphere fully from a side to opposite side, and upper surface 51 and 54 be allow with lower surface backward with the opposite complete sphere that generally moves that travels forward.

The supplementary features of prosthese shown in these figure are, provide to be arranged in the groove centre that epipyramis lower surface and following vertebra upper surface produce and to be adjusted to coupling upper and lower vertical ridge 57,58 wherein.Like clearer illustrating among Figure 11, nuclear 50 and upper plate 53 and lower plate 55 make prosthese axis 60 move to back 1/3 of prosthese and make that going up radius of curvature center (CUPR) A and following radius of curvature center (CLPR) D aligns passing on the vertical axis of ACR.Through previous embodiment, major part 61 is positioned at axis 60 forward and less important parts 62 and leans on the location, back.In addition, the inferior axis of nuclear 50 aligns with vertical axis 61.In addition, nuclear 50 forward and backward vertical edge is smooth and aligns abreast with inferior axis 64.

Under the constraint of parallel end plate and complete ligament tension, attempt causing separating of equality 6,7 and 8 to provide-6.87 ° of angles and provide 3.13 ° of angles the effect of 10 ° of prosthese 49 bendings to β to α.

In Figure 12, the epipyramis 65 that has rotated angle α and β almost be represented by dotted lines and overlap corresponding to the vertebra 66 that rotates 10 ° (γ) around ACR.Parallel and its spacing the separating from minimized point of end plate represented to keep making in this position.This is corresponding to the position of maximum ligament tension (MLS).The nuclear of the dual recess prosthese shown in Figure 11 and 12 moves forward in bending.Therefore accomplishing these required ligament tension amounts is positioned at the prosthese mid point than prosthese axis and has under the situation like the design of Figure 10 A and Figure 10 B littler.In this configuration, under the constraint of parallel end plate and complete ligament tension, attempt causing separating of equality 6,7 and 8 to provide-6.94 ° of angles and provide-3.06 ° of angles the effect of crooked 10 ° of prosthese to β to α.In this example, symmetrical by the prosthese of 70 expressions along next axis, and it under static state overlaps with the vertical axis of upper and lower vertebra 71,72.Figure 10 B illustrates once more epipyramis 71 traveling angle α and β is rotated 10 ° of effects of comparing with epipyramis with respect to ACR.Can find out, epipyramis 71 possibly move not with actual vertebra 74 and the kinematic similitude that is designed to the prosthese that prosthese axis/inferior axis overlaps with the vertical axis that passes ACR.

Figure 14 illustrates the angled view of the prosthetic appliance 49 with nuclear 50, upper plate 53 and lower plate 55.

Figure 15 A and 15B illustrate selectivity embodiment of the present invention, and wherein prosthese comprises the nuclear 75 with upper plate 76 and lower plate 77.Nuclear 75 has protruding upper surface 78 and recessed lower surface 79.As being relevant to Figure 12 and 13 described embodiments, inferior axis 80, prosthese axis overlap with the vertical axis of the ACR that passes down vertebra 81.Because lower surface 79 is protruding, so it is much littler than upper convex surface 78.Similarly, the lower surface of upper plate 76 be depression and have a configuration of mating with surface 78.Lower plate 77 has than coupling sunk surface 79 longer protruding upper surfaces examines 75 forward and backward motions above that with permission.

Figure 15 B illustrate epipyramis 82 how to cause upper plate 76 and nuclear between 75 relative motion and examine 75 and lower plate 77 between relative motion.

Embodiment shown in figure 13, prosthese axis are asymmetric and examine 75 major part and be positioned at before the prosthese axis.

Figure 16 illustrates another prosthese 83 that is made up of the nuclear with protruding upper surface 85 84, and wherein upper surface has the radius of curvature littler than recessed lower surface 86.In this embodiment, upper and lower surperficial 85,86 both have be positioned at nuclear 84 belows the radius of curvature center.

Upper plate 87 has recessed lower surface and lower plate 88 with surface 85 couplings and has the long many protruding upper surfaces 89 of specific surface 86 to allow reasonably forward and backward moving.In addition, the convex surfaces 89 of lower plate 88 extends to straight horizontal planar surface 90.This prevents to examine 84 effectively and moves forward above the end of convex surfaces 89.

Figure 17 illustrate except upper surface 92 have than the longer radius of curvature of lower surface 93 with prosthese 83 similar prostheses 91.In addition, the lower surface of upper plate 93 is depression and longer than the length of its cooperation upper surface 91.Lower plate 95 has than the longer convex surfaces of cooperation sunk surface 92 length.In addition, at the back segment place of convex surfaces 96, acclivitous straightforward face 98 is set as preventing nuclear 99 to surpass the device of convex surfaces 96 terminal motions.

The front end of convex surfaces 96 also extend to be used to prevent to examine 99 be moved beyond curved surface 96 front ends straight horizontal cross section 97.

Should be noted that prosthese 83,91 is shown in Figure 16 and 17 more practically is inserted between the upper and lower vertebra, and they have similar trapezoidal and non-rectangular shape.Therefore, though surface 90 with 97 and above-mentioned surface be described as level, in fact, they are that the general orientation on upper and lower surface of inclination and common and upper and lower vertebra is parallel.Should also be noted that surface 90 and 97 is inclined upwardly or even downward-slopingly need only them and can prevent to examine 84,99 travel forward.

So far described different prostheses concentrate on the various characteristics of imitateing intervertebral disc.The useful add-on assemble of prosthese that is designed to imitate the intervertebral disc characteristic comprised shown in figure 18 be with 100, it is designed to the effect of approximate simulation ligament (ligature), and also is the proal stop device of prosthetic nucleus in one embodiment.

Be with 100 to be made up of textile fabric 101, wherein textile fabric comprises the longitude and latitude fibril, forms the mesh-like Weaving pattern.Upper and lower terminal 102,103 are provided with connecting plate 104,105, and connecting plate 104,105 has separately and is used to insert screw to be attached to the hole of vertebra up and down respectively.

Yarn fabric 101 preferably is dimensioned to promote the cell growth in the gap space between line/fibril, and finally causes the ligament growth between the upper and lower vertebra.

According to an embodiment, this band is the tough band forms of being processed by suitable inflexible weaving and absorbable material of prosthese.Textile material be designed to allow fibrous tissue inwardly growth to replace the function of prosthese ligament when absorbing again at it.

According to an embodiment, this band is the tulle form of being processed by line or polymeric material.

This band preferably can elongate or shrinks with the mode that is similar to ligament.

Aspect above-mentioned different prosthese material therefors, end plate can be by processing such as titanium, cobalt-chromium steel or ceramic composite.Usually, they have with the Rough Flat Plate of vertebrae adjacent surface surperficial.In order to help that this plate is fixed to vertebra, they are provided with the wing or ridge described in can the embodiment shown in Figure 13 and 14, perhaps they can be provided with and be used to be carried on the curved surface on the adjacent vertebral bodies end plate.

The upper and lower surface of nuclear and the adjacent flex surface of upper and lower end plate preferably smoothly connect to strengthen the joint.Centronucleus can be by processing with end plate material therefor materials similar, but also can be by processing such as poly plastics of UHMW or polyurethanes composite.

The radius of curvature of each of prosthese curved surface is preferably in 5 to 35mm scopes.

The overlay area of prosthese end plate can be different shape but the danger that is absorbed in the adjacent vertebrae is minimized.

Be connected surperficially though in depression and convex surfaces, described the various joints of nuclear and upper and lower plate, should be noted that other surface profile also can comprise in the present invention.

For example, nuclear and the cooperating surfaces of lower plate can be ellipsoid but not cylinder, so that limited relative motion therebetween is provided.

Above mathematics explanation provides the behavior of the artificial disc prostheses with doublejointed connection.Each of the modification of the upper and lower surface profile that the different embodiments contemplate of described this prosthese are possible.They comprise that biconvex rises, dual recess and raising and lower recess, go up depression and lower convexity.Above-mentioned equality has been described under the therebetween situation of doublejointed prosthese, position and orientation that fixing vertebra down moves on epipyramis.With reference to constant and through the variable angle of rotation of variable α and β described epipyramis with respect to the motion of prosthese upper surface and prosthese lower surface with respect to the motion of vertebra down.The orientation of epipyramis is expressed as:

cos ^-1(cosα·cosβ-sinα·sinβ)

The position of point E is just above dish gap center of rotation, and the epipyramis lower limb can be provided by following equality

x(α，β)＝-(sinα·cosB+cosα·sinβ)·Ldsk+(cosα·cosβ-sinα·sinβ)·Cdsk-cosα·Bask+Pdsk

y(α，β)＝-(sinα·cosβ+cosα·sinβ)·Ldsk+(cosα·cosβ-sinα·sinβ)·Cdsk-cosα·Bdsk+Pdsk)

Wherein constant definition the size and the function type of prosthese.

There are 4 kinds of dissimilar prostheses that are described below in the relative size that depends on parameter L dsk, Cdsk, Bdsk and Pdsk:

They are (describing through nuclear shape)

1. biconvex rises

2. dual recess

3. raising, lower recess wherein go up radius greater than following radius

4. raising, lower recess wherein descend radius to explain the locomotory mechanism of these 4 kinds of prostheses greater than last radius equality 1-3.The length that COR is connected to the line of an E is:

$l(\mathrm{\&alpha;},\mathrm{\&beta;})=\sqrt{x{(\mathrm{\&alpha;},\mathrm{\&beta;})}^2+y{(\mathrm{\&alpha;},\mathrm{\&beta;})}^2}$

Wherein α is the angular displacement of top with respect to mid portion; β is a mid portion with respect to the angular displacement of lower part and l is the ligament of center of rotation that connects a part and the used skeletal structure (or prosthese) on top; Wherein x (α, β) and y (α β) is different functions.

Preferably, " ligament " comprises any elongate member, especially has to a certain degree stretching, extension or the element of stretching and contraction or compression.

But the value of calculation of alpha and β is to produce the minima of l.L can be regarded as the side of motion segments.Therefore because it is elastic, can be regarded as its behavior and as spring and thus hour has minimum elastic potential energy as l.When l is minimum or maximum, but the calculated equilibrium position.On the mathematics, this can be defined as gradient vector is zero:

$\&dtri;l(\mathrm{\&alpha;},b)=\left[\begin{array}{c}\frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&alpha;}}\\ \frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&beta;}}\end{array}\right]=\left[\begin{array}{c}0\\ 0\end{array}\right]$

Under the situation of zero gradient vector, for the little change of α and β, the elastic potential energy of prosthese is changed to zero, and this prosthese is in the equilbrium position.Yet, when this equilbrium position is the maximum of l, can find out that α and β will cause l to reduce and the equilbrium position is unsettled than microvariations easily.On the mathematics, this can be expressed as:

$\left[\begin{array}{c}\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;\; \&alpha;}}\\ \frac{{\mathrm{\&delta;}}^2\mathrm{\&delta;\; l}}{\mathrm{\&delta;\; \&beta;}}\end{array}\right]=\left[\begin{array}{c}-\mathrm{Ve}\\ -\mathrm{Ve}\end{array}\right]$ Or $\left[\begin{array}{c}\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;\; \&alpha;}}\\ \frac{{\mathrm{\&delta;}}^2\mathrm{\&delta;\; l}}{\mathrm{\&delta;\; \&beta;}}\end{array}\right]=\left[\begin{array}{c}+\mathrm{Ve}\\ -\mathrm{Ve}\end{array}\right]$ Or $\left[\begin{array}{c}\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;\; \&alpha;}}\\ \frac{{\mathrm{\&delta;}}^2\mathrm{\&delta;\; l}}{\mathrm{\&delta;\; \&beta;}}\end{array}\right]=\left[\begin{array}{c}-\mathrm{Ve}\\ +\mathrm{Ve}\end{array}\right]$

In these cases, prosthese might and be in poised state by balance accurately, though little disturbance meeting causes it to be in maximum deflection or extended position fast.

Can find out prosthese 1) and 4) a unsettled equilbrium position had.When this situation occurs in the outer COR of coupling axis or axis.Through increasing the radius that upper and lower joint connects, the value of gradient vector will and be taked maximum deflection or stretches localized trend and will weaken for less negative.

Yet, prosthese 2) and 3) have a characteristic of the positive second order local derviation of l:

$\left[\begin{array}{c}\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;\&alpha;}}\\ \frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;\&beta;}}\end{array}\right]=\left[\begin{array}{c}+\mathrm{ve}\\ +\mathrm{ve}\end{array}\right]$

Define the equilbrium position by following formula:

$\&dtri;l(\mathrm{\&alpha;},\mathrm{\&beta;})=\left[\begin{array}{c}\frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&alpha;}}\\ \frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&beta;}}\end{array}\right]=\left[\begin{array}{c}0\\ 0\end{array}\right]$

In other words, exist as l and be hour equilibratory α and β value.This balance is stable, self-correcting or from middle, because turbulent any trend will be tending towards making l elongated and therefore increase the elastic potential energy of this system from the equilbrium position with prosthese

Therefore, prosthese 2) and 3) have stable equilbrium position and be self-correcting or from middle.

During COR on attempting coupling prosthese axis, the equilbrium position is at (as α=β=0 time) on the neutral position.When the outer COR of coupling axis, neutral position (when α ≠ β ≠ 0)-when the CR of coupling before the prosthese axis is left in the equilbrium position, and the equilbrium position is in the stretching, extension and when the CR that matees after the prosthese axis, the equilbrium position will be in the bending.

When the radius value that connects when upper and lower joint is big, the variation of the equilbrium position that causes because of the coupling skew will reduce.

Figure 20 A illustrates ligament length 1 with respect to the β of the prosthetic nucleus with protruding upper surface and recessed lower surface and the three-dimensional curve diagram of α, and wherein the radius of curvature of upper surface is greater than lower surface.As an example, last radius is 36mm, and radius is 12mm down.

Visible from Figure 20 A, shown three-dimensional curve has been indicated the minimum ligament length of being represented by trough in the curve.

In this accompanying drawing, having X and Y skew is zero, and its expression prosthese axis aligns with patient's center of rotation and corresponding to the L among Figure 19 A and the 19B.

It is the effect of the L of 1mm that Figure 20 B illustrates the prosthese introducing value identical with Figure 20 category-A type.Move on the direction opposite with L the equilbrium position.Can use mathematical method to optimize this variation of equilbrium position and make this prosthese more insensitive the variation of Y skew (L) or X skew (patient's CR is moved down).

Figure 21 illustrates the prosthese for Figure 20 A, and ligament length is with respect to the two-dimensional view of angle of bend.Visible at this accompanying drawing, exist by near the obvious trough the center of rotation of crooked extension angle 0 expression.This curve be shown clearly in any motion that this prosthese leaves from center of rotation all can cause the stretching, extension of ligament length and therefore ligament tend to return its minimum length of center of rotation naturally easily.

More than different with prosthese with biconvex nuclei of origin.For the biconvex nuclei of origin, the curve of above-mentioned mathematical equation is separated shown in Figure 22.Becoming from the analysis of this curve, it is obvious that, do not have the minimum ligament length that equilibrium point is provided.In fact, bidimensional curve chart shown in Figure 23 illustrates equilibrium point and how to be positioned near the center of rotation of biconvex nuclei of origin and any motion that nuclear leaves center of rotation is shown and all can cause reducing of ligament length, thereby the tendency that this nuclear leaves equilibrium point reduces.

Figure 24 A illustrates wherein, and prosthese has another embodiment of the present invention of dual recess nuclear.As the embodiment shown in Figure 20 A, the 20B and 21, in this embodiment, near nuclear, there is equilibrium point.Therefore this equilibrium point is corresponding to minimum ligament length and be provided at the tendency that this nuclear under the situation about removing from center of rotation returns equilibrium point.

The ligament length that Figure 24 B illustrates the dual recess prosthese changes, wherein go up radius equal 36mm and down radius to equal that 36mm and Y skew squint with X be zero.Therefore can find out that for the radius that equates, the curve chart of mathematical model illustrates, there is not the tendency of the motion that causes returning the equilbrium position in the equilbrium position of motion leave to(for) prosthese.

Unshowned bidimensional curve chart has the similar profile with Figure 21.

Should be clear from preceding text; If expectation produces the prosthese with self-correcting capability; Wherein this ability causes any motion of leaving equilibrium point all will cause nature to promote prosthese to return the tendency of equilibrium point, then with respect to Figure 20 A, 20B, 21 and the described embodiment of the present invention of 24A suitable solution is provided.Yet should also be noted that and also can use other embodiment of the present invention of having described, even they do not have this from ability placed in the middle.This is because can carry out other change so that the motion of this prosthese is remained in the predetermined margin to total prosthese.

All prosthese can both mate the COR on the axis.When COR was outside axis, then prosthese can be only through stretching or shortening collateral ligament (Delta L) perhaps through adopting anomalous orientation (Delta A) to mate.For given skew, Delta A and Delta L can reduce more greatly through making radius.

All prosthese can both carry out pure flat moving.Prosthese 2) highly realizes through the impairment dish.Prosthese 3) highly realizes through the increase dish.

Desirable prosthese has

1 stable equilibrium point

2 handle the optimum capacity of the outer CR of axis

This is 2) or 3)

Preferred embodiments be have big as far as possible radius 3).It has the pure flat attendant advantages of moving of opposing (because soft tissue needs to elongate).

Second preferred embodiments is 2), it has the advantage of free relatively translation.

Have preferred 2) or 3) clinical setting.

Can the radius ratio of prosthese 3 be set under the situation at COR coupling physiology normal rotation center, have the arc that equates between upper and lower joint connects.This can be realized by following formula:

R1*α＝R2*β

Wherein but calculation of alpha and β are with coupling CR.

This will mate the wearing and tearing of upper and lower joint connection and be the most effectively using of contact surface zone.

The ability of calculation of alpha and β makes it possible to prosthese is designed.

Realize these, the required ideal range of the ratio of vertebra in lumbar vertebra and cervical vertebra is 3: 1-10: 1.

In lumbar vertebra and cervical vertebra, preferable radius is 5mm and 50mm.

Prosthese 2 does not allow the stroke (travel) on each articular surface to equate.Preferably, can use the mathematical model basis to realize the optimum selection of radius ratio such as the desired parameters of the required ratio of angle α and β to this prosthese.In lumbar vertebra and cervical vertebra, desired proportions is 2: 1-1: 2.In lumbar vertebra, for each radius, preferable radius is between 8-40mm.In cervical vertebra, preferable radius is between 6-30mm.

Figure 10 A to 11B and 13A to 13F illustrate the prosthese with dual recess profile.Figure 15 A, 15D, 16 and 17 illustrate the prosthese with protruding upper surface and recessed lower surface.The radius of curvature with upper surface that prosthese version shown in Figure 17 is preferable is used greater than the form of recessed lower surface.The lower surface of upper plate preferably has the profile with prosthese upper surface coupling, and the upper surface of lower plate has the profile that matees with the prosthese lower surface.But should be appreciated that this does not represent the profile that the entire upper surface of whole lower surface and the lower plate of upper plate has coupling.Therefore, show preferable prosthese configuration with reference to Figure 19 A with above-mentioned preferable upper and lower surface profile.Shown prosthese 110 is symmetric and have level and smooth curved outer top edge and a lower limb about central vertical axis.This prosthese is illustrated as skew backward and its nuclear 113 is retained in the rear region of upper and lower plate 111,112.

The upper surface of lower plate 112 has the convex shape rear region with nuclear 113 relative depression outline.

The summit of elevated regions is with respect to the center back skew of prosthese.Elevated regions is symmetric and extend in the depression trough in both sides about its off center vertical axis, thereby general outline that should the zone is the shape of sinusoidal segment curve.

Each of trough all extend to the elevated regions both sides be bent upwards in the surface and provide backward and actuator forward with the restriction prosthese with respect to lower plate forward and motion backward.

Upper plate 111 has backward the recessed lower surface of skew, and this lower surface has and is configured to limit nuclear 113 and extends the edge downwards with respect to the rear portion that upper plate 111 moves backward.

Visible like Figure 19 A, the radius of curvature of upper plate lower surface is greater than the radius of curvature of lower plate upper surface.In various situations, radius of curvature has in fact in the common origin on the prosthese central vertical axis that is positioned at below the prosthese.

Figure 19 A also is illustrated in the nuclear 113 that aligns with the central vertical axis that squints backward towards the anatomy central axis 114 on the equilbrium position.

Collateral ligament 115 is illustrated as and is connected upper and lower vertebra 116, between 117.Ligament 115 is from axis 114 offset distance L.

Figure 19 B illustrates prosthese 112 and how to receive the influence that epipyramis 116 rotates backward with respect to following intervertebral disc 117.

As shown in the figure, collateral ligament 115 rotates, and the disorder of internal organs heart (CR) rotates and upper plate 111 turns to unstable position with nuclear 113.Because it is different with lower surface to examine the radius of curvature of 113 upper surface, so ligament 115 stretches and exists it to return the conatus of the equilbrium position shown in Figure 19 A.The difference of radius of curvature means that also intervertebral disc 116 will be with respect to intervertebral disc 117 rotations and translation down.

The radius of curvature and the prosthese upper surface radius of curvature therefore of the lower surface through increasing upper plate might increase employed prosthese at the COR of this prosthese degree of stability under the ACR drift condition.

The required increase of the radius of curvature of prosthese upper surface and therefore the radius of curvature of upper plate lower surface strengthened prosthese and returned the easy degree that is centered close near the equilibrium point of its central vertical axis.

According to an embodiment, the central vertical axis of prosthese is far away more from the center of rotation skew of skeletal structure, and the radius of curvature of prosthese upper surface is big more.

The radius of curvature of prosthese upper surface in lumbar vertebra preferably 30 and 50mm between, in cervical vertebra preferably 20 and 40mm between.

Because the ratio of the radius of curvature of prosthese upper surface and the radius of curvature of prosthese lower surface is in preset range, the increase of the radius of curvature of prosthese upper surface will cause the corresponding increase of the radius of curvature of prosthese lower surface.

The length of the elevated regions of lower plate upper surface (measuring from front to back) is preferably confirmed according to the typical stroke of intervertebral disc in typical spinal column.

All embodiments of prosthese preferably have be set at intervertebral disc after as far as possible closely to mate the prosthese axis of normal physiological center of rotation.

Should be appreciated that if any prior art publication is referred among this paper, then this quoting do not constitute a part of admitting this publication formation general knowledge known in this field in Australia or other any country.

Claims (37)

1. prosthese that is used for spinal column; Comprise: be used to be attached to epipyramis top, be used to be attached to down the lower part and the mid portion between said top and lower part of vertebra; Wherein said top comprises the lower surface area with first curvature radius; Said mid portion comprises surface area with second curvature radius and the lower surface area with the 3rd radius of curvature; Said lower part comprises the surface area with the 4th radius of curvature, and wherein squint with respect to the central vertical axis of passing said upper and lower vertebra and/or said upper and lower part backward in the center of the radius of curvature at least two surfaces.

2. prosthese as claimed in claim 1 is characterized in that, at least one squints from said central vertical axis backward in said the 4th radius of curvature and the said first curvature radius.

3. prosthese as claimed in claim 1 is characterized in that, squints with respect to said central vertical axis backward in the radius of curvature center of each of said surface.

4. prosthese as claimed in claim 1 is characterized in that, the radius of curvature of each of said surface is centered close to behind the prosthese in 1/3rd.

5. prosthese as claimed in claim 1 is characterized in that, said mid portion has subcenter axis and main central axis, and wherein said subcenter axis is positioned to pass the radius of curvature center on the said second and the 3rd surface.

6. prosthese as claimed in claim 5 is characterized in that, said subcenter axis tilts with respect to said vertical centre axis.

7. prosthese as claimed in claim 5 is characterized in that, said main shaft is positioned to pass the rear end of said mid portion and the center of front end.

8. prosthese as claimed in claim 1 is characterized in that, the lower surface of lobed upper surface of said mid portion and depression.

9. prosthese as claimed in claim 1 is characterized in that, the said upper surface of said mid portion is depression and lower surface said mid portion caves in.

10. prosthese as claimed in claim 8 is characterized in that the radius of curvature of said mid portion upper surface is greater than the radius of curvature of said lower surface.

11. prosthese as claimed in claim 8 is characterized in that, said lower surface first curvature radius is substantially the same with said second curvature radius.

12., it is characterized in that said the 3rd radius of curvature is substantially the same with said the 4th radius of curvature like claim 8 or 11 described prostheses.

13. prosthese as claimed in claim 1 is characterized in that, said first, second, third and being centered close on the vertical axis that squints backward from the said central vertical axis of passing said top and lower part of the 4th radius of curvature.

14. prosthese as claimed in claim 1 is characterized in that, said top has smooth basically lower surface forefoot area.

15., it is characterized in that said lower part has smooth basically upper surface forefoot area like claim 1 or 14 described prostheses.

16. prosthese as claimed in claim 1 is characterized in that, said lower part has the upper surface that comprises back surface area and front surface area, and wherein said back surface area comprises about passing the symmetric elevated regions of vertical centre axis of said mid portion.

17. prosthese as claimed in claim 16 is characterized in that, the said upper surface rear region of said lower part is included in the recessed region of said elevated regions both sides.

18. prosthese as claimed in claim 1; It is characterized in that; Said mid portion has protruding upper surface and convex lower surface, and the upper and lower surface of wherein said mid portion radius of curvature separately is configured to said mid portion can make said mid portion be driven to the localized equilbrium position of central axis of the said prosthese in edge basically with respect to the motion in preset range of said top or lower part.

19. prosthese as claimed in claim 1; It is characterized in that; Said mid portion has concave upper surface and recessed lower surface, and the upper and lower surface of wherein said mid portion radius of curvature separately is configured to said mid portion can make said mid portion be driven to the localized equilbrium position of central axis of the said prosthese in edge basically with respect to the motion in preset range of said top or lower part.

20., it is characterized in that said second curvature radius is greater than said the 3rd radius of curvature like claim 18 or 19 described prostheses.

21. prosthese as claimed in claim 20 is characterized in that, the ratio of said second curvature radius and said the 3rd radius of curvature is between 3: 1 to 10: 1.

22. prosthese as claimed in claim 1 is characterized in that, said second curvature radius is between X and Y.

23. prosthese as claimed in claim 1 is characterized in that, the center of rotation of wherein said top, mid portion and lower part squints with respect to the central vertical axis of passing said prosthese backward.

24. prosthese as claimed in claim 23; It is characterized in that each surperficial radius of curvature is configured to any one or the motion of a plurality of part in preset range can make said mid portion be driven to the localized equilbrium position of central vertical axis of the said prosthese in edge basically.

25., it is characterized in that said prosthese has the center of rotation corresponding to the equilbrium position of said mid portion like claim 1 or 24 described prostheses.

26. prosthese as claimed in claim 1 is characterized in that, the major part of said mid portion is configured to when said upper and lower vertebra perpendicular alignment the forward location of anatomy center of rotation at spinal column.

27. prosthese as claimed in claim 1 is characterized in that, said prosthese comprises the stop device that when said prosthese is arranged in spinal column, is positioned at after the said mid portion with before.

28. prosthese as claimed in claim 27 is characterized in that, said stop device comprises the end regions of said upper and lower part.

29., it is characterized in that said mid portion has the equilbrium position by the following formula definition like claim 1 or 26 described prostheses:

$\frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&alpha;}}=o$ $\frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&beta;}}=o$

And

$\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;}{\mathrm{\&beta;}}^2}=+\mathrm{ve}$

And

$\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;}{\mathrm{\&beta;}}^2}=+\mathrm{ve}$

Wherein α is the angular displacement of said top with respect to said mid portion

β is the angular displacement of said mid portion with respect to said lower part, and

L is the ligament length in use of center of rotation that connects a part and the skeletal structure on said top, wherein:

$l(\mathrm{\&alpha;},\mathrm{\&beta;})=\sqrt{x{(\mathrm{\&alpha;},\mathrm{\&beta;})}^2+y{(\mathrm{\&alpha;},\mathrm{\&beta;})}^2}$

Wherein x (α, β) and y (α β) is different functions.

30. prosthese as claimed in claim 1 is characterized in that, said mid portion is configured to have upper surface and lower surface, and its equilbrium position with respect to said upper and lower part is defined by following formula:

$\frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&alpha;}}=o$ $\frac{\mathrm{\&delta;l}}{\mathrm{\&delta;\&beta;}}=o$

And

$\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;}{\mathrm{\&beta;}}^2}=+\mathrm{ve}$

And

$\frac{{\mathrm{\&delta;}}^{2}l}{\mathrm{\&delta;}{\mathrm{\&beta;}}^2}=+\mathrm{ve}$

Wherein α is the angular displacement of said top with respect to said mid portion

β is the angular displacement of said mid portion with respect to said lower part, and

L is the center of rotation that connects a part and the skeletal structure on said top LigamentLength in use,

Wherein:

$l(\mathrm{\&alpha;},\mathrm{\&beta;})=\sqrt{x{(\mathrm{\&alpha;},\mathrm{\&beta;})}^2+y{(\mathrm{\&alpha;},\mathrm{\&beta;})}^2}$

Wherein x (α, β) and y (α β) is different functions;

Wherein minimum with respect to the less variation of the length l of angle α or the less variation of β, if said mid portion is removed from said equilbrium position, then said length l all increases in both sides, said equilbrium position.

31. prosthese as claimed in claim 30 is characterized in that, each of said variable α, β or l confirmed with respect to the center of rotation of said prosthese.

32. prosthese as claimed in claim 1; It is characterized in that having to be configured to have and have any one motion of removing from said equilbrium position the said part then tend to make that said prosthese aligns with said equilbrium position from installing between two parties with equilbrium position of aliging and said prosthese from the central vertical axis of anatomy central axis skew if said top, mid portion and lower part are configured to said prosthese.

33. prosthese as claimed in claim 32; It is characterized in that said device certainly placed in the middle is included in said top and/or mid portion can make said prosthese tend near said equilbrium position from the middle predetermined surface configuration that is respectively applied for the said first, second, third and the 4th radius of curvature when said equilbrium position is removed.

34. prosthese as claimed in claim 1 is characterized in that, said top, mid portion and lower part have stable equilbrium position.

35. prosthese as claimed in claim 34 is characterized in that, said equilbrium position is with respect to the vertical centre axis skew of passing said prosthese.

36. prosthese as claimed in claim 34; It is characterized in that, if there is relative motion in the said first, second, third and the 4th radius of curvature between being configured in said top, mid portion and lower part arbitrarily then said prosthese is driven into said stable equilbrium position.

37. prosthese as claimed in claim 1 is characterized in that, said top is simulated possible rotation of intervertebral disc and translational motion approx when said prosthese is attached to upper and lower vertebra.

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